Ready, steady, dig: workers get burrowing on record-breaking tunnel down south

The tunnel will stretch for 2,300 metres and will be built near the Czech border. GDDKiA

Engineers have started work on what will be the longest road tunnel in Poland, hewing their way through the hard rock of a mountain range in the south west of the country.

Once completed TS-26 tunnel will stretch for 2,300 metres under the Kaczawskie Mountains, taking the S3 expressway from near the town of Bolków to Kamienna Góra, and the Czech border.

The tunnel represents a significant engineering challenge so the General Directorate for National Roads and Highways has decided to employ a burrowing technique called New Australian Tunnelling Method (NATM).

Engineers will use the latest techniques in tunnelling.Grzegorz Momot/PAP

NATM is viewed as both revolutionary and cost effective. It is based on the properties—and the monitoring of—rock masses during construction, and can be adjusted during the process. It relies on the inherent strength of the surrounding rock mass being conserved as the main component of tunnel support. In other words, the rock around the tunnel is used to stop it collapsing.

Once competed the entire structure will be run from a Tunnel Management Centre, which will come bristling with automatic systems that will monitor traffic and keep drivers safe. Emergency points with SOS phones are to be located every 125 metres, while water hydrants will be placed every 250 metres. An emergency helicopter landing pad will also be built nearby.

Even though work on the tunnel should be completed in 2023, the General Directorate for National Roads and Highways is already inviting people to take a virtual ride through the tunnel as part of a presentation on it.

The Kaczawskie Mountains, under which the tunnel will burrow.Marek Angiel/PAP

The 3D visualization shows safety is a paramount feature in the project. The project consists of two, two-lane tunnels running parallel with each other, and they will be will be connected by nine evacuation passages located every 250 metres, as well as one emergency passage for rescue services.

At the moment there are 15 tunnels longer than 100 metres in Poland, with eight others being built right now but the tunnel between Bolków and Kamienna Góra stands out among them due to the difficulty of the construction process.